Terminal lug and mounting block



Jan. 31, 1956 T. J. OBSZARNY TERMINAL LUG AND MOUNTING BLOCK Filed April 9 1951 TERMINAL LUG AND MOUNTING BLOCK L Thedore J, -(lbszarny Chicflgo, Illa, assignor to Guardian Electric Manufacturing Co., Chicago, Ill.,a corporation .oflllinois ApplicatiouA pril 9, -1951,'Serial No.-21 9,923 '3 Claims. crew-220 The present invention relates to terminal lugs and terr'ninal blocks'on which-such lugs 'are mounted, whichare, by way'of example and not limitation, especially suitable {for use in conjunction'with hermetically sealed, electro- "magnetic -relays.

Hermetic'ally sealed relays as "heretoforeproduced; in-

clude a 'relay component or device, completely enclosed in a sealed eharnberot a metallic housing or case, and having conductor wires connected to the various sets of pole contactsofftherelay and'to the terminals forjsupplying of electrical energy to'the coil of 'therelay. Such Wires extend in sealed relation through a bulkhead or partition 'Wall in the case and are connected to terminal lugs carried "on a terminal block or mounting panel. The project'ing ends-orterminal portions of the conductor wires,

which extend intothe sealed'chamber and are connected to the various sets of pole contacts and terminals associated with the'coilofthe'relay, are e'xtendedthrough the wallet the terminal block, and also extend into openings .iforme'd in theterminal lugs.

Theterminal lugs heretofore employed each have a depending tubular sleeve extendingthrou'gh the Wall of the block'with the free end of the sleeve spun outwardlyto provide a hollow r'ivettype'of connection of the lug to the block. The interior of the sleeve is threaded for there ception of a terminal screw for securernent thereto of'a terminal clip-onthe endof a conductor Wire of an'electrical'circuitto be controlled by the relay.

More particularly the present invention is directed to jterminallugs and terminal blocks of the type 'adaptedfor handling of relatively heavy electrical currents, such as *inzthe rangeof 100 amperes. For such use,"thete'rmihal lugs necessarily are formed of sheet metal stamping's "of =rather'heavy gauge metal. Byr'easonof the connection of "the l'ugsto the terminal blocki'n the manner above referred to, it frequently happens that the'lug is caused to rot-ate incident totightening or loosening of the terminal screw Which secures the terminal clip of a conductor wire to the lug. It has'been 'found'that frequently when installing a rlay-in'the field, in the process of connecting of conductor wires, of electrical circuits to be controlled,

tothe terminal lugs, by'means of 'the terminal screws, the -force employed in tightening or loosening such screws tends to place the conductor'wires, extendingfrom the relay proper within the sealed chamber, under a shearing stress, and frequently results in shearing of such wires, a'nd'thusrendering the total "hermetically'sealed relay device non-usable, and necessitating re-woi'kin'g thereof and 'reinstallation of new conductor wires from the pole contacts or the terminals of the relay coil.

One of the objects of the present inventionis to provide a novel and improved form of terminallug and terminal block especially adapted for handling of heavy electrical .Currents, and which is constructed and arrangedso as to eliminate the above mentioned objectionable conditions. Another object is to provide a novel heavy duty terminal'lug and terminal block construction which limits rosimple in eonstruct'iohQdurablc in use being economically manufactured.

2,733,422 Fiterited slam-'31, 1-956 tative movemenvdr thedfig when it is attached *to the further object i810 i m novel ll y ing of the conductor wire which extends through 'tlre-block 'andis'soldered to the lug. U 7

"Still anotherobject 'is'to provide an improved "duty enamel lug and terrrlinal block which is relatively and capable or Other objects and advantages of this invention=willflie apparent from the followin'g' description taken in' connection'wi'th the accompanying drawing'in-which: I V

Figure lis a face "viewof a relay assembly provided with terminallugs'and a terminal block embodyiir'g' the present invention;

Figure 2 is-a 'vievv in sideleva tionof the relayassembl'yywith certain p'ortionsbroken away to show'details of construction;

Figure "3 is'a'nenla'rged seetienar view through the'ter- Figure '4 isan enlarged, fragmentary face view of a "portion of'the'terminalblock showing one ofthe terminal Figure '5 *is'a sectional-view taken mines-#5 on Figure4;and l Figure 6is anerilarged, perspective view oftlre termi- 'nal lug embodying thepresent invention.

In "Figures 1 and Z'of'the drawing,'there is disclosed'a "conventionalhermetically sealed type of relay wherein "the relayprop'er "is indicated generally at 10in dotted outline,

totally enclosed "in 'a cup=shaped housing or case 11,

formed of sheet metal. Adjacent the open end'of the case,

'thereis formed an inwardly projecting head or shoulder 12, against'which isseated 'abulklread 1 4 "in'thenature'of a partition wall, 'theperipheral edges-of wliich'are sealed to the inner wall of the case, i as by solder, "as indicated at 1 5." Itis-to be understood that thebulkhead is provided 'Wlthasuit'able fitting, not shown, for [conveniently evacuating the-ldsed chaniber'of the "Case, below theblilkhad,

connected by conductor wires, asindicated at 17,'which extend through the bulkhead 14, and which are sealed with -respect"the"reto by c onve'ntional glass bead sealing devi'ces, indicated generally at 18.

Theout'er end ofthe case 11 is closed by a terminal block 20, formed of "suitable .electrical'insulating' material, 'theiirn'derside of whichis formed with a depending peripheral *fiange '21, for snug fitted engagement in the open end of the case. The free end portions 17a of the conductor wires 17 extend t'liroug'h the insulating terminal block 20 and are connected to suitable terminal lugs, as willbe'hereinafter described. A d

For each terminal in the nature of a pole contact, and each terminal connection for the coil of the relay proper, .therevarep rovided corresponding terminal lugs on the outer faceof- .the terminal block 20, and to which lugs may be attached, the ends of the respective conductor 3 parallel, spaced apart ribs 22, defining terminal mounting areas.

' The construction as represented in the drawings is for a relay having two sets of pole contacts for which there is provided, on the outer face of the terminal blocks, four terminal lugs indicated at 25. Because the construction herein disclosed is for heavy duty usethat is, the circuits being controlled utilize heavy current, in the range of 100 amperes, the terminal lugs 25 are formed apertures 28 and 29, as clearly seen in Figure 4 of the drawing, the large aperture 28 accommodating the sleeve 26 of the terminal lug therein, and the sleeve being of such length that it projects beyond the inner surface of the main wall of the block, and said end is spun or rolled outwardly in the nature of ahollow rivet for firmly securing the lug in place on the block. The aperture 29 accommodates therethrough the terminal portion 17a of a-conductor wire which extends into the U-shaped notch 27 of the terminal lug. It is to be understood that any excess length of such conductor wires aresevered so that the end of said wire projects substantially flush with the upper surface of the terminal lug. The terminal ends 17a of the conductorwire are then firmly secured to the respective terminal lugs by solder, as indicated at 30, and which connection serves as the medium for securing the total terminal block and terminal lug assembly to the open end of the case 11.

As may be seen in the drawing, the terminal lugs 25 are so dimensioned and located as to provide a surface extending in relatively close relation to an adjacent rib 22 of the terminal block, and attention is directed to the fact that the construction as represented in Figures 3-6, inclusive, of the drawing, represents the parts at approximately twice actual size, and, therefore, it will be appreciated that one edge of the terminal lug is caused to be positioned extremely close to the adjacent rib 22 on the terminal block, andthus any tendency for rotative movement of the terminal lug is immediately limited by abutment of the lug against the adjacent rib. It is to be noted that the opening or aperture 29 through which the terminal portion 17a of the conductor wire from the interior of the casing 11 extends, is of a size slightly in excess of the diameter of the wire 17a, so as to permit a limited amount of movement of the terminal portion 17a of the conductor wire with the lug 25, before abutting against a rib 22, without imposing any shearing strains upon said portion of the conductor wire, incident to the rotative movement of the terminal lug.

The inner wall of the sleeve 26 of the terminal lug is threaded, and is adapted for the reception of a terminal mounting screw 32 for securing a terminal clip 33 carried on the end of a conductor wire 34, which, in turn, is

. connected in and constitutes a part of the electrical circuits being controlled by the relay. 10.

It will be'apparent that in tightening or loosening the terminal screws 32 in connection with securing or removing the terminal clips 33 with respect to the terminal lugs 25, there is often a tendency to impart rotative movement to the terminal lugs 25, and except for the blocking arrangement provided by the ribs 22 on the terminal block, there is a possibility that such rotative movement of-the terminal lugs would effect shearing of the end of the terminal portion 17:: of the conductor wire 17, which would, as above indicated, render the total relay assembly defective by reason of the severance of a con ductor wire attached to a terminal lug and would necessitate removal of the total relay device and re-working the same by introduction of a new conductor wire 17, which may in some instances cause serious delay, as for example in aircraft construction, and necessitate the expenditure of substantial time and added cost in the matter of re-working of the relay device.

Although the terminal lugs 25, as shown, are provided with relatively straight sides, obviously, if desired, they might be formed with projecting nibs at opposite ends for cooperative engagement with an adjacent rib of the terminal block to serve as an abutment for limiting rotative movement of the terminal lug. The ribs 22 also serve to permit close spacing of the terminal lugs and serves as an electrical barrier topreclude possible short circuiting across terminal lugs.

At the lower portion of the terminal block, there is provided a pair of terminal lugs, as indicated at 36 which may be understood to be the same as the terminal lugs constituting the invention disclosed in my co-pending application, Serial No. 219,922, filed April 9, 1951, now Patent No. 2,701,870 dated February 8, 1955. The terminal lugs 36 may be understood to be connected to conductor wires extending into the case 11, the opposite ends of which are connected to terminals for the coil of the relay. It is possible to use lugs of the type designated at 36 for controlling the coil of the relay because of it being possible to utilize considerably lighter current, as compared to current which may be employed in the circuits being controlled through the sets of pole contacts of the relay proper.

Although I have herein shown and described a preferred embodiment of my invention, manifestlyv it is capable of modification and rearrangement of parts without departing from the spirit and scope thereof. I do not, therefore, wish to be understood as limiting this invention to the precise form herein disclosed, except as I may be solimited by the appended claims.

I claim as my invention:

1. A terminal mounting block formed of electrical insulating material, having a terminal mounting face provided with one or more outwardly extending ribs defining separate terminal mounting areas, and a plurality of terminal lugs connected to said block in said areas, and each having a tubular sleeve seated in an aperture formed in said area, with the free end of the sleeve extending beyond the undersurface of the block and spun outwardly for firmly securing said'lug to the block, said lugs .each being formed with an opening, spaced from the sleeve, and registering with an aperture in the block for the reception in the respective aperture and opening of the terminal portion of a conductor wire disposed at the side of said block opposite to said terminal-areas, said lugs each having portions disposed in close proximity to said ribs for opposing rotative movement of said lugs.

2. A terminal mounting block formed of electrical insulating material, having a terminal mounting face provided with one or more outwardly extending ribs defining separate terminal mounting areas, and a plurality of terminal lugs connected to said block in said areas, and each having a tubular sleeve seatedin an aperture formed in said area, with the free end of the sleeve extending beyond the undersurface of the block and spun outwardly for firmly securing said lug to the block, and lugs each being formed with a peripheral, U-shaped notch, spaced from said sleeve, and registering with an aperture in the block for the reception in the respective aperture and having a tubular sleeve seated in an aperture formed in.

saidarea, with the free end of the sleeve extending beyond the undersurface of the block and spun outwardly for firmly securing said lug to the block, said lugs each being formed with an opening, spaced from the sleeve, and registering with an aperture in the block for the reception in the respective aperture and opening of the terminal portion of a conductor wire disposed at the side of said block opposite to said terminal areas, said aperture being substantially larger than the cross-section of the Wire to permit limited relative rotative movement between said block and said terminal lugs and wire, said lugs each having portions disposed in close proximity to said ribs for opposing rotative movement of said lugs and precluding imposition of shearing strains on the wire in the zone between said'lugs and terminal block.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS Great Britain June 19, 

